Kind of funny I just came back to the states from Canada on a visit. Getting into Canada was fairly easy, I have no passport just birth cert and govt ID. Coming back was fun, I got the full extra search/pat down coming back into the states, I was told this was because, get this, I had no carry on luggage. All I had was my wallet, cell phone, pants, shirt I had on. Apparently this means I need extra searching. I found that highly amusing. Plus US customs grilled me about 10X worse then Canadian, which was easy.